Characterization of a pectinolytic activity in Azospirillum irakense

Khammas, K. M.; Kaiser, Paul

doi:10.1007/978-94-011-3486-6_36

Cited by 17 publications

(9 citation statements)

References 8 publications

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“…Azospirillum irakense, the fifth Azospirillum species, was found in association with rice roots. This is the only species that has pectinolytic activities (Khammas and Kaiser 1991). The other species of this genus are A.…”

Section: A New Speciesmentioning

confidence: 99%

Azospirillum– plant relationships: environmental and physiological advances (1990–1996)

Bashan¹,

Holguín²

1997

Can. J. Microbiol.

546

268

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This review presents a critical and comprehensive analysis of the developments in environmental and physiological studies related to Azospirillum interactions with plants based on information published between 1990 and 1996. It was designed as an update of a previous review with a similar scope. Apart from an update, this review emphasizes the central issues of Azospirillum research today, such as coinoculation with other microorganisms and hormonal studies, shows the less researched areas, and proposes possible avenues for the exploitation of this bacterium in areas other than agriculture.Key words: Azospirillum, bacterial inoculation, plant–bacteria interaction, plant growth promoting rhizobacteria, rhizosphere bacteria.

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Section: A New Speciesmentioning

confidence: 99%

Azospirillum– plant relationships: environmental and physiological advances (1990–1996)

Bashan¹,

Holguín²

1997

Can. J. Microbiol.

546

268

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“…There is no obvious evidence for producing cellulase by Azospirillum and the reports of pectinolytic activity of Azospirillum brasilense are contradictory. Several authors (Plazinski and Rolfe 1985;Tien et al 1981) have reported pectinolytic activity but others (Khammas and Kaiser 1991;Myers and Hubbell 1987) have found no evidence of pectin breakdown by A. irakens. However, it is also possible that Azospirillum does not produce the complete enzyme set required for the infection but induces plant to produce these enzymes by e.g.…”

Section: Discussionmentioning

confidence: 94%

The participation of the cell wall hydrolytic enzymes in the initial colonization of Azospirillum brasilense on wheat roots

2007

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The effect of cellulase and pectinase on bacterial colonization of wheat was studied by three different experiments. In the first experiment, the root colonization of 3 wheat cultivars (Ghods, Roshan and Omid) by two A. brasilense strains (Sp7 and Dol) was compared using pretreated roots with cellulase and pectinase, and non-treated with these enzymes (control). Although the root colonization varied greatly among strain-plant combinations in controls, the pre-treatment of roots with polysaccharide degrading enzymes significantly increased the bacterial count in roots, regardless of the strainplant combination. This might be an indication that cell wall may act as an important factor in plant-Azospirillum interaction. In the second experiment, the root cellulase activity of the same wheat cultivars treated with and without the two Azospirillum brasilense, strains (Sp7 and Dol) was compared. The pre-treatment of wheat roots with Azospirillum enhanced the cellulase activity of wheat root extracts. Thus, the cellulase activity might participate in the initial colonization of wheat roots by Azospirillum. The comparison of the cellulase activity of root extracts within inoculated and non-inoculated seedlings showed that the inoculation had enhanced the cellulase activity in root extracts, but this effect was directly dependent on the strain-plant combination. Strain Sp7 stimulated the highest cellulase activity in cv. Roshan, but strain Dol induced the highest enzyme activity in cv. Ghods. In the third experiment, several growth parameters of those 3 wheat cultivars treated with and without those two bacterial strains (Sp7 and Dol) were compared. The highest magnitude of growth responses caused by Sp7 strain was in the cv Roshan, but Dol strain stimulated the highest growth in cv Ghods. Therefore, effective colonization may contribute to more growth responses.

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“…Later, extension into the various aerial parts of the plant takes place only after expressing two degradative enzymes pectinases and cellulases, specialized in degrading cell walls of plant tissues (Dong et al 2003;Compant et al 2008). These two degradative enzymes are most common and efficient technique deployed by vast majority of endophytes for colonization by Azospirillum irakense (Khammas and Kaiser 1991), Azoarcus sp. (Hurek and Reinhold-Hurek 2003) and others.…”

Section: Entry and Distribution Inside Rootsmentioning

confidence: 99%

Mechanistic insights on plant root colonization by bacterial endophytes: a symbiotic relationship for sustainable agriculture

Jha

Panwar

2018

Environmental Sustainability

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Plant-microbe and soil interactions are one of the oldest muse for multi-disciplinary researchers. Plant growth promoting microorganisms influence the host physiology by secreting regulatory chemical signals in the vicinity of plant roots and play a key role in the enhancement of plant growth and expansion. The present review deals with the in-depth understanding of steps involved in host tissues colonization by bacterial endophytes. The molecular insights of these events, particularly for endophytic bacteria, are poorly documented till date. The endophytic bacteria must coexist with the host plant and capable of colonizing the internal plant tissues without being recognized as a pathogen. A proper understanding of exchange of signals between the host plant and bacterial communities is required which may facilitate the development of new strategies to promote beneficial interactions between them. This knowledge can be instrumental in agricultural practices as well as for phytoremediation of pollutants. Keeping these facts in mind, the present review attempts to explore the systematic understanding of steps involved and molecular insights of plant colonization events by endophytic bacteria. We conclude that molecular mechanisms and factors affecting endophytic bacterial colonization deserve more research attention in order to exploit their beneficial aspects for sustainable agriculture and environment.

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Characterization of a pectinolytic activity in Azospirillum irakense

Cited by 17 publications

References 8 publications

Azospirillum– plant relationships: environmental and physiological advances (1990–1996)

Azospirillum– plant relationships: environmental and physiological advances (1990–1996)

The participation of the cell wall hydrolytic enzymes in the initial colonization of Azospirillum brasilense on wheat roots

Mechanistic insights on plant root colonization by bacterial endophytes: a symbiotic relationship for sustainable agriculture

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